1990 GS500E - Bogging when revved. Unsure what is the problem.

[NathanAU]

Hi guys,

First post on here - I've read thread after thread on here and still haven't got quite a good clue of what's going on.

I open the throttle and it dies. Both when it's warm and cold. It happens when I'm at a stand still or taking off, or sometimes when I change up gears.

I've taken the carbs apart several times to triple check the diaphragm, float height, passages, o-rings, general quality of parts, etc.

A few things to note:

- Float heights are correct (to my knowledge around 14.6mm +-1mm)
- Needle clip position is correct
- New sparkplugs.
- Slide guide is worn on left carb. Partially cracked wall in one area.
- Diaphragm quality is okay on both. No tears or holes.
- O-rings are all there and okay.
- Gaskets are all there and okay.
- Frame petcock is okay.
- Hoses are all okay.
- No vaccuum leaks between carb and cylinder head as far as I'm aware.

All I can think of at the moment.

Pls send help.

[The Buddha]

Revving = slide has to lift. However, when not under load, it will hit redline by the time you get to 1/4 throttle.
So your issue is likely in that 0-1/4 throttle range - AKA pilot jet and maybe float level.

Under load, your slide is the issue if it wont rev.

Cool.
Buddha.

[NathanAU]

So your issue is likely in that 0-1/4 throttle range - AKA pilot jet and maybe float level.

I'll give that a crack and see how we go. It's midnight here so I'll mess around with the pilot jets, needles and floats tomorrow and see how we go.